Gambler jokes.

Find a capable person to guide him so that he will never know how to make money but how to lose money.

Because if you don't let him do it, it will only be a blow to him. For example, you like to do a job or something, but he doesn't agree with you, opposes you, points at you all day and advises you. What would you think?

So to stop him, it is better to help him, support him and make him an able person in this field.

Use his addiction to guide him on the right track and let people give full play to their potential.

Moreover, there is no right or wrong in every industry, only serious and not serious, and hard work is not hard. You must know this better than I do.

For example, Einstein's achievements come from his obsession and persistence in scientific research.

Then you must find a way to make him an expert and a stock expert. Wouldn't that be better? (Maybe it's really possible)